1. Field of the Invention
This invention relates to electronic devices and more particularly to computer input/output devices.
2. DESCRIPTION OF THE PRIOR ART
All digital computers are essentially the same. They usually comprise: an input device for entering information; a memory unit for storing information; an arithmetic and logic unit for performing computations; a control unit for causing the computer to proceed through the problem by executing the proper operations; and an output device for displaying information. Computers reduce higher mathematics to arithmetic and arithmetic to counting. Digital computers have the capacity to regulate themselves by processing information which the computer has itself produce. Once the computer has received a computer program which is precise instructions regarding the operation of the computer, the computer is ready to solve problems. The computer can organize the problem it is currently solving into separate steps. The computer can use the results obtained in one step to execute the next step, and the computer can display the answer to the problem on some output device such as a cathode ray tube (CRT) or a digital television.
Computers can be used to perform complicated scientific calculations, keep inventories, or monitor industrial processes, etc. In order to perform the foregoing functions, information must be entered into the computer. Information may be entered into a computer by means of a keyboard entry device, such as a multi-purpose display which consists of a CRT and a keyboard that has many different keys. When an operator wishes to change a numerical value that is displayed on the CRT, he identifies the displayed parameters he wants to change by depressing the keys on the keyboard in the sequential order that corresponds to the identification code of the selected parameter, and then he depresses the keys that equal the value he wants the changed parameter to have. The changed parameter is entered into the computer and displayed on the CRT. Information may also be entered into a computer by using a light pen, a CRT and a keyboard. The operator takes the light pen and points to the parameter listed on the CRT which he wants to change and depresses the keys on the keyboard that correspond to the value that he wishes the selected parameter to have. By utilizing the first method for entering information into the computer, the operator has to use a light pen, then the keyboard. This change in equipment requires the operator either to put the light pen down and then operate the keyboard or operate the light pen and keyboard with both hands. If the operator decides on the first alternative, he is wasting time putting the light pen down. If the operator selects the second method for entering information into the computer, he will be operating the equipment with both hands and consequently he may be using his less favored hand to enter information into the CRT.
The computer, CRT and keyboard are usually arranged as part of a computer operator's station. A computer operator's station usually contains all of the equipment that the operator requires to control and monitor the computer system. The reason why the operator's station contains all or most of the equipment to monitor and operate the computer is that computers are fast and expensive. Computers usually can process information quicker than the information can be entered into the computer and if the computer is monitoring some process, the information might have to be entered rapidly to insure that the process is functioning properly. Therefore, it is important that information be entered into the computer as rapidly as is possible.